This invention relates to an improvement in the construction of pleated paper filter assemblies of the type used to filter the air intake on diesel locomotives. More particularly, the present invention is related to an improvement of the filter assembly disclosed in U.S. Pat. No. 3,402,531 wherein the wedge supports disposed between adjacent filter panels arranged in a V-configuration are interlocked with the filter frame to prevent displacement of the media and supporting wedges and resulting media damage upon the filter assembly being subjected to non-uniform loading.
U.S. Pat. No. 3,402,531, the teachings of which are hereby incorporated by reference, discloses a compact filter assembly for providing a large filter area in a relatively small and inaccessible space which employs individual filter elements each including pleated paper filter panels mounted in a zig-zag configuration in a housing. A plurality of the elements may be mounted in a side by side relationship and stacked relationship to provide the assembly which is particularly useful for filtering the intake air of a diesel locomotive engine or the like. To provide support and prevent buckling of the panels as a result of air passing therethrough, V-shaped wedges are disposed between the adjacent pleated paper filter panels in the downstream wedge spaces defined by the "mouth ends" of the Vees. While such a configuration has provided an excellent and highly successful filter assembly, problems have arisen when the filter assembly is subjected to uneven loading which can result from excessive moisture on the media or localized build-up of foreign matter thereon.
As a result of such uneven loading, ruptures in the media have occurred adjacent the downstream end of the assembly. It has been discovered that the damage occurred as a result of the media and the adjacent supporting wedges being forced by the uneven loading laterally away from the rear pans of the filter assembly which extend about the downstream ends of the filter panels to secure the panels in place. During such an occurrence, the media acts like a membrane and is extruded under pressure through the lateral separation and ruptures. When the loading is relieved, the media and wedge supports return to their original positions adjacent the pans disguising the cause of the failure. The present invention prevents such occurrences without adversely affecting the performance of the filter assembly or the cost of its construction.